Liquid-level-indicating system



May 6, 1930. J. D. sARTAKoFF 1,757,061

LIQUID LEVEL INDIQATING SYSTEM Filed March l5 1926 3 Sheets-Sheet l 4l {HIIIII IIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIHI las" ATTORNEYS.

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May 6, 1930. J. D. sARTAKoFF LIQUID LEVEL INDICATING SYSTEM Filed March 15 1926 May 6, 1930. J. D. sARTAKor-'F 1,757,061

LIQUID LEVEL INDICATING SYSTEM Filed man 15 192e a sheets-sheet s INVENTOR. fa/'a'/of' A TTORNEYS.

Jay

rammed Mays, Y1930 .mex D. enmarcar; or new Yoan an. Y.; 'assieme er 10aa-finir reir. D.

irorncoitronnfiioigon NEWjzonn, n. y?, n'ooiigoirs'iiionon NEW Yonliijf,Y AND Y ONE-HALF 'ifo KHETai-i oei'i'r'oiilnaioii, or Ynirl; N. Y., A 'ooRPoRA'rionfoiiv NEW Yonai f ;Lienmiami-imitating sesam i. Applicatioirieannarch i5, 5192s; seriarziio. 94,650; i

Y rl`^his invention is a'lliquid ,levelindicating system adapted for the automatic indication of Vliquid levelsatiirernote points' troinjtlieV containers of the liquid, `and is particularlT adapted to" he used rior indicatingthe liquid level or quantityofgasoline contained Within undergroundsupply tanks in gara-gestilling sta-tions and-the like.` vfIam aware, hO-Wp `V ever.,- that the invention is 'adapted'gfor .gene eral appli-cation and is `notliifnited to this specific 'use'.

Tlieohject ofthe inventionhhi'oadlystated,

is to :provide afsimple, -yet thoroughly effr-v cient and accuratesystein for the indication ofliquid levels andfone wherein atmospheric' changes, `such' as variations temperature, will not effect Aerrors inindication. l

Under prior practice, the, most'.'cominon` inethod of accurately-ineasuringthe contents ofiinderground tanks consists 'in 'the ennployfV nient of a measuring stick '-WliiohisI thrust down through:aJ measuring pipeto the base of the-tank. This is-a fairly accurate :method of measuring,- but is `inconv,engientV andas a resulty is not-carried out `as'frequently,as .cirf' ciunstances may Wart-ant, so that, Aininany instances, tanks become V.euipty lvvrithout knowledge 'of this 'approaching f condiition until feedof liquid from the .tank ceases.V 4

Y \vNuinerousexpedients have'been resorted .to

in an atteniptto replace, byinorefconvenient, 'ineans, the practice of usinga measuring stick, but, for one reason or another, such expedieiitshave not-proven'satisfactory In' the majority of cases, they are "ei-ther too complex and difficult vto ii'istallfor ,thev are Vnot reliable'.V .lis generalproposition. iafll ,Y those measuring systems?, adapted to-he" asso# ciated with iindergroiind itanks and .enijoloy`-'4 .ing an above 'ground indicatonfreqfuire ein tensive and expensivealterations Ein tlietank installation. n Y *i Y n practically 1 all cases, it is necessary to dig down tothe tankand cutzaivavafpoition of the tank to pei-'Initfthe@introduction of'V suitable naar Y merita-inem for r operating .the indicating element. This is an expensive pro-l cedurey and unless li'nco'i"posated` intaiiks atvr the timelof installation :ofsuch itarilrsgfity .is

'coiummuie paginas if-Whitt not ordinarily .feasible to add l'such indicating .systerntoaninstalilationn Y i f 1,757,06i

Y l/Viththe=foregoing considerations,and oth erswellpiecognized in theart, in inind, `the present `r invention embodies numerous objectsA Y and features directed Lto Athe provision of Ha siinplegand'eilicient systeinccapable ,ofincorporation Iinto an old tan'k'installation Witljiout requiring anyv excavation o i;y in lany-` `Wise changingthe iiista'llation. lhisfis .a

inatterfof irst .importance from apracti'cal l standpoint., Y.

In A.ta'inkl installations, it is the practice :to bury :theftank several4 feet 'belowl the ysurface of; the ground and to provide aineasiiiing pipe leading. from` the ground .surface to vthe stituted Vand. V.propotioned With *respect` ,to

vrtheV said. pipe tliatfor installat'ionv of .the

device, itis only necessai'y'tou loivei'v such portion of the system through Vsaid'pipe into thefmk M211). beine fiordviaedjfm themas- Sea'hhg" the: @Persie Off the pipe.

,Y @hat Vportion,or the device adapted to `be" positionedin tlietank consistsofaleat ivliich is aflix'ed'zto a cylinder' gpitovided therein with a. inohijl'e piston. The cylinde`risin practice l preferably Uf-shapedfand is `formed in a cylinderhlock inonntedto tilton a horizontal axis under theimpulse'ofthe.ioat for the purpose "of shiftingjthe inobile .piston longitudinally offtvthevcylinder- The twoopposite ends of the "cylinder chamber are connected by con-4 f'duits -Which le'ad upwardly through vthe {illinglpipeand through tliecap thereof, and

thence are 'ledtof a` U tube" positionedin any suitablelocation,Where itv is desired eindig cat'etheliquidlevelin the't'ank, ,Ofii'eoff f il" conduits leads from ,-O'ne end of the t l f Vto one'a'rin ,ojfthe"v U tuloeand the other conduit leads freintlieotheiend f the Vcylinder to -the ot'lie'i-ariiiof the U tube.` y

The U tube fontaine; liquid readin U tube byvarying..pressuresprod l arms of the'rtub'e'alolvedthe cliii'ni'i li; fe to Asa tiltingol the cylinder on its pivot under they Y iinpulse ot the float. Thus, the position of the float controls Vthe positions of the reading column.

In order that variations 'inteinperaturd Will not affect the correct indication of? the liquid level, both conduits, to Which I have referred, are preferablyvalyed so that when desired they may be simultaneouslyffvented to lpermit the communicationof atmospheric air` into both ot them, in order that a balanced condition maybe etfectedltherein, when the float is at its minimum level, so that the reading column may be ad]- usted tozero position.

It is yessential that during the venting of the' conduits to balance 'tlrepressures as stated, the float must 'be in apredetermined position if accurate indication of liquid levels in the' tank is to be' obtained, and I'therefore provide means operable Vfrom above the ground to manually place v,thel float in proper V- position 'during' this .venting` operation.

The' provisionot means for venting the system and for vproperly"positioning: the'tloat during this operation is of pronounced prac'- tical importance and absolutely novel in this art; It constitutes a marked stepin advance f of. prior practice, since by lthis* feature ab. solutely accurate indication ot the liquid lev'el 'in the tank can be had.V Furthermore, this canfbe obtained in an apparatus'capableof vin the tank. 3 y Y rThat has beensaid applies both to tanks ivherein liquid is adaptedv to be pumped .fassociation with an underground tank Withexcavation or. any'clianges out necessitating therefrom and toY systemsfivherein lthe liquid is forced therefrom under hydraulic pressure.

l tailed descriptionand claims and froinftlie yAnotherfeature of the present invention consists in supporting the mechanism,adapted to be positioned Within thestank, upon al tubular 'post or standard adapted to extend,

when" the'v installation is "complete, Ifrein a point above the ground tothe base oit thetank.

. s uch tanks and must .be pumped off from time to time. flthas heretofore been the'practice to. introduce'a-tube into thevtankor'tliis puinA pose',.. but in accordance Withthe present` in: vention, this is rendered unnecessary by the use of a `hollouT supportingpost. 1

' :Numerous other features and advantages will `loe apparent/from'the hereinafter deaccoinpanying'drawings.-

The accoinpanyingV drawings illustrate one Y practical f embodiment ofi the invention, but

the construction thereinshown is to be under stood as illustrative,l only, 'and not as defining the limits of theinvention.

y igure l shows, in a moreor less diagram;

matic nianneigthe presentf'invention as in-y stalled inan underground tank, the tank beino sho'vvn-in section. Y l y Figure-Qk isan enlargedaelevation otrtlie portioasof the ,apgaratus shown `Within the tank injFigu-re 1, j y, u

i Figure 3, 's'. an edgeelevation ofthe nieclianisni shown in Figure 2 as viewed from the right hand lsido of Figure 2.

:Figureis aifragmental section taken in tlie'plane of the line 1 /i of Figure 3.'

- tiguref'isiasection onjthe'li'ne -fof l Figure 6 vis la fragmentalsec'tion,taken Y y in theplane of the line 6 -6fof Figur'efl ;V and,` Figurefl'lis a-section taken' in the plane of t-hefiineTf Figur@ 6-1 i l Referring to the drawings, l indicates a tankftvhich is shoivnasfburi'ed below the `ground level f2.` f A pipe V3 extends from with; in a recess avvithin'the-ground surface doivnivardly to and is secured tothe tank` This pipeisnfound on all installations and is gen? e'rally provided for the-insertionV ota ineasur- In associating the present invention ivithf such anfinstallation, a rcrap 5 is`proviclecl for the pipe 3. The center-of'this cap is'cut auay andl stepped platea' is yfitted 'int-o the hole and heldin placefby screiv'sgb. yThis plate has acentral ,hole in which is introduced' a tubular supporting post Gland a gland 7 is as-V 'ice Y sociated ivitli thefhole to preclude leakage at this point.v 'Thepost' is 'sufficiently' long to rest upon the bottom ofthe tank as shown in Figure 1 `ivlienA` the cap is screwed onto the f pipejfand on the post 6 is mounted the eratingine'chani'sm of tlie system. Y. 1 l This operating mechanism, `which is best shown in Figures 2 to 5,'einbodies a cylinder Vblock8 mountedtotilt on a horizontal pivot r9.' .The cylinder` block may be of any suitable construction, but, in practice, I preferably make it ofy substantiallyy rectangular form.' In the block are formed twolvertic'al passages 9a and 1,0,iv'hich areconnected-.bya lon-f Vgitudinal passagell, the end yof which is pluggedlv as Vshownl at 12 (see Figure ll) .i The passages 9a, IO andV l-lmcollectively constitute a substantiallyv U -shapedcylinder adapted to containa mobile piston 13, .wliich,in practice, is preferably mercury, ithough.itmay'be ot.

any Vother suitable heavy liquid. The inercuryfis introduced While the passages. 9 vand 10 are openandsaid passages Vare thereafter 'closedbyinsertinggplugs 14. A

. Asshown in Figure.5,the plugsarel ofin``Y verted cup shape and at the lower edge of each is formed a'thin liangerlffbent inwardly as shoWninFigure 5 .to clamp'inplace a suitable Y filtering diaphragm 16 `'adapted to periiiitof agvevge'ei the passage I of air While effect-'nelly preclud- .Y

ing the passage of mercury. Thisarrange- `ment provides Withineachplug'a chamber 17 partitioned off from the c ylinderciiamber by a diaphragm 16.` p

As shown in Figures 4E and 5, 'thefwaliof `the block 8 and the skirt `oJf-eechl'lug"` 214 4is `pierced at18 to provide' forfthe insertionfofthe free end of arelativelysina-ll tube,where by the interior of the chamber `17e' may be [placed in communication Withthe linterior of the corresponding tube. Thus V4thecham4` ber 17 of the passage '9a is connected by mean-s of a. tube 19, While the'tube'20,similarlyleads from the chamber associated `,With Vthe .,fpassage 10. These two tubes lead to acondeiiser or sump 21, which is "mountedupon.agfolamp 22. Theclamp 22is inthe form oli-a sleeve i which surrounds the post 6 and also" embraces a clamping; jaw 23 and theu-pper end of a bracket 24. The braoketQ-et, as ``shown in Figures 2 and 3, extenderdownwardly'from the sleeve'22 and isoffsetto-provide suliicient space` between thej od '.set portion'of the braoket and-the'post 6 to permit-thecylinder lbloclrto be positioned in such space. j

The Vpivot 9 vwhichxsuppoidis the block for tilting movement is j o'urnalled ati one end lin y the bracket24- andat'its otherA end in'theipest 6. Screws 25 extend loosely through the sleeve 22, threadthrough the'braclet 2lvand bear against the jaw 23, sotliat by tightening these screws, the bracket may lbe tightly clamped to the post. "lf desired, f the lpa'i'ts may be soforrned, asbyprovidin-g' a lugfon the bracket, that-both ends fthelpivotvg Will be supported on VVthe braclet,or the jj'aw 23 which carries a leat 27k at its Vouter"endzalld may be extended downwardlyStov support-one end of the pivot 9, irl-'order thatthe pivotrmey v be mounted for vertical adjustment' on `the post 6; This, however, is matter'o'f detail.

v In order that the conduits'lortubes 19 and f 2O may not interfere vwith tilting .movement of the cylinder block 8,;'each tube .isfprefere ably formed into a .pluralityy of spiiaflcoiwo lutions 19t and'awhich enoi'rcleitlie pivot 9 on the opposite `sides ofthecylinder block, as shownbest in Figures and E.

Secured to one endoffthelcylinder"block, preferably in rigid'nianner,fis a rod'26 it isthe -rise and vfall ofthe float with therise and'fall of liquid level in'lthe ltankwhich im partsjthe tiltingrmovenient tothe cylinder block. lUnthei'o'd 26is fixed .anadjustable weight 28,1the pnrpsefoffwhich fwil'lbeiheref inaftermore' fully explained; f f

' I havestated'that thetubes19sandi20le'ad to a `'condenser "or sump-2l; This sump; is

shown ain vFigure 2 with lthe .cover plat'e rie# moved `and from'thisfigure, it Will be fnoted that the sump embodies two chambers'QQand' 30. The tube 19extends through :thebottern ofthe chamber" 29 tofabove the center thereof and the ztubei20 similarly projeotsintothe i' chamber. BO. From the chambers and l30 'eX-tendconduitsjll9 .and 120.. Theseconduit's', as shown in `Figure 2, extend fromapoint 'below' the -rupperv ends of the'tubes 1.9 and. 2O

upwardly through-the upper Walls of the respective:chambers-andfnpwardly along the post 6- through the cap V5 being provided Wherethey pass,through'thefeap,-Witlisuit- 1 able glands A to preclude leakage; of pressure 'orsuctionat this'point. Beyondthe capf the v lconduits leadltd-indicating ,means .hereL inafter more icullyfexplained.

rThe purpose/of the sulnp 21lisltotrapout anycondensationr orQvnioisture"which may accumulateliii:theconduits1s-19and 1.20 andthe base of eachschamber ofdthesumpis.prefer-- kably provided `Withla suitablelabsorbing medium 32to 'absorbthis moisture, softhatit' will i Y ,i

not-1pass,fdownwardly .to `the .cylinder block.

"Inpractice, theflparts'ltlnisfiar described f 4are so shaped and proportionedthatltlrey; may

be'introduced into orireni'oved fromthetank througlrthepipe .-3.V .Inasmuhiasthe float :rod 26 `Will .normally `extend lin ia].lateralfdirection, it is desirable to provide. means for-,moyeing said'rod into 'substantially.parallel re-V ,p lation 'with the posti 6 When itfisxde'sired'to 1nf troduce or .remove"'the .operating mechanismv described. in .order to `accomplish 'this arefsu'lt inia.thoroughlyleicient.and expeditious f l manner, mount a .cross head 33 .'o'nslidingl movement, saideross headibeing 'guided :be tween-.the post `6 and the parallellower por- Vtioniotthe .braeket 24: andsecured' to the. cross Yhead isan upstanding iinlgerzi. u

is a rod 35, theflowerendof Whiclris secured to the cross headzat 36,sothatthel cross head may be reciprocatedffrom 4the .ground level` bylifting'ori depressing the :rod 35. The

finger 34 is so shaped that when the rod`35 is littedt'o lift the 4cross head,fthe upperend ofthe linger 4Will-engage `with the vcylinder block onthe opposite slide ofthe :pivot -9 from the'loat and continued' elcvation'oflthe cross` moved 'intoalinement rfitlrthe remainder of the operating means, so thatthe, complete operating means may be lrerniovedfby vmerely unscrewingethe screws 5"(to rlel'easezthevplate 5:l and. lifting out fthefentire Vapparatus trolling, apparatus,.the procedure isof course the same .except thaLWhen..the plate His screwed. downtight, the fred 35de forced downwardly tiolrelease the cylinder bloc'kto permit of' operation-thereofhy f'the.lo'at-. A

l guide 6a fixedo-n' thepest 6 .bes 1radial-.ly eee through the pipes "When inserting thelcoiitending arms to centi-alize the post Within the v installation 'Without v any in the installation; f

. The imechanism whichv I have thus far de-VV lo Vscribed servesas the operating means for inpipe 3 during Vremoval or replacement of the apparatus.

.It will therefore be apparent that the operating -means ofthis invention may be .readily Y and expeditiously associated with any tank Change whatsoever dicating adjuncts adapted -to b e positioned Y at a distance from the tank such, for example,

vas in the oliiceof a garage or service station.

Theindicating.meansfmay partake of various forms Awithout departing from thev invention, but, avery satisfactory form,'is .shownl in the drawings, wher'ein`36 designatesA aY U tube provided with twoupstanding arms 37 and 38, the upper ends of both ofY which are secured to a valvecasing 39. The valve casing'is formed'fwith two straightthroughpassages 37 a andy 38ste.theformeroffwhich'the conduit 119 leads, and to the latterof which *"theV conduit 120yleads, as shownbestV in Fig- .Y Y

ure6: Stuing boxes40'operate to preclude leak'- age where the conduits enter the valve'casing.

`From the passages 37a ,and 38, lateral'vent passages` 37b and`38b extend'to the lateral face of the casing:(see Figure 7) and a pair of needle valves 37c and 38? simultaneously cooperate with .both of these `vent passages.

i Both needle valves are -supported in a com'- mon fholder,41'controlled byk an operating sere/w42. When thescrew 42 is tightened, both of the needle valves are drawnto the left in Figure 7 to simultaneously.tightly seal both vent passages, but when-the screw is loosened, both needle valvesare withdrawn from the ventpassages for the purpose of .venting the' system in order that balanced atmospheric pressures may be produced in both arms of the U tube, as well as in the'conduits Y119fand 120 and Athe tubes 19 and 20.' VThiswill of courseproduce a similar condi-.

tion within the chambers atboth ends of the mobile piston infthe'l cylinder block. The importance of the 'ability' to thus vent the system will be'hereinafter more fully explained.

The U tube 36 contains a suitable liquid constituting a reading column 43 and it is found in practice that when the needle valves shown in Figure 7 are seated tightly vto close theisystem, the position of `the reading column V will be determined by the position ofthefloat l 2 7. .v VThe reason' for thiswillbe clearly apparent when it is borne in jinind that the rais- 1ng or lowering of the float will impart movement to the mobile piston within ythe cylinder to produce increased pressure at one end of the cylinder andacorresponding decrease in pressure; atthe other end ofthe cylinder.

These variations in pressure will be communi-V catedthrough vthe conduits to the U tube and will produce like conditions wth-intherespeo tive arms of such tube. These different pressures will manifestly causealshifting of the reading column in strict accordance withthe movements ofl the float. l

In practice, the U tube is mounted within a suitable casing 44, in which the tube is positioned in upstanding relation and occupies a plane substantially perpendicular to the front of the casing which is formed by a glasspanel` V45. The sides of the casing are preferably provided -on their inner faces with vertical guides 46 with which cooperate the lateralv edges of a strip of suitablel material 47 on which is delineated agraduated scale 48. The Vscale card 47 ispositioned back of the [arm 37 of the Uf-tube and forwardlyof kthe arm 3,8',

so that the graduations are positioned -immediately back ofthat arm of the U tube which contains that portion of the yreading Vcolumn serving as an indication.

Vthe casing inany suitable manner are a pair` of slides 50and`51, the former .of which car,- ries a Wire 501"L Vand, thevlatter of which carries a wire 51a. yBoth these wires extend acrossthe-casing forwardly of the arm 37v of the U tube. and may be manually adjusted Y.

ico

vertically to enable comparative readings to 7 be made, as will `be Vhereinafter morel fully explained.v l

y In practice, the operating mechanism of. the i j system is'introduced into the tank through the pipe 3 and the cap 5 positioned thereon in the Vvmanner. hereinbefore described; Thereafter the casing 44 with the U tube and other parts ofthe structure carriedgthereby lis mounted in any suitable location, and these two major elements of the system are-connected together by the conduits 119 iand V120.y The system is novvjcompletely installedrand proper adj ustment ofthe parts is undertaken. This is accomplishedby liftingtherod35 to elevate the follower and force the cylinder 8into a position.whichjcorresponds to the minimum` liquid level in the tank 1, asfindicated in the dotted linetposition ofthe float land rod in Figure 1. With thecylinder in this posi,y

tion, the needle vvalves 37s and 38C* are .unseated to vent the.' system and as a result of this ventingthe measuring liquid 43 infthe U tube comes into a positionwhereintheliquid columnwill raise Vto the samelevel inboth arms of the U tube. The scale. card'47 is now i vertically adjusted inthe guides-46 until the graduationon. the scalecard'fshowinga corrj 11,757,061 fi f at the upper end of the reading column .in-

the arm 37 of the U tube. e n

The needle valves STG and SSGf-are now seated, the rod .35 is depressed into the full- V line position of Figure 1,- and the apparatus The ioat will immediately rise totheV liquid level in the tank, l and itsI positionvwill be Vaccurately indicated bythe reading'column whenread in conjunction-with the' scale card. Thereafter rise or fall of the. liquid level 1n the tank l vwill be accurately indicated byf the reading columrn'but at suitable intervals the system maybe vented to obvriate any ln-pV aocuracies in; reading which.-.1night result from the presence of improper` unbalanced pressuresin the conduits;k

It will be of course understood in this oonnection that whenever the system isvented, the cylinder should be forcedY into a positionv corresponding to minimum liquid llevel in Y the tank l in order that correct relative'v ad# justment between the parts of the'system be had.

y In practice, the ability to 'check-thee. 'system from time to time withouty removing 'any' of the partsofthe system and without unse'val-r` ing the tank l is of .marked praoticallimfV portance, as will be apparent to those skill'ed in the art. The building upfof false p res` sures which wouldy result. in` falseV readingsv without proper meansfor obviatingthis; is, by the present invention, entirely overcome.

I have referredto the wires V5.0 and 51?'.V These are associated with"L the scale Cardin order that c-emparativereadings may be hadv when desired', as,- for example, .when itis Vdev sired to ascertain the amount of liquid in troduced into. o r drayvfnefrpni thetank 1 dur--l ing any*particular Vperiod yor operation.

rlfhesewires are readily adjustable vertically.

ofthe scale card and' may be manually manip- Vulatedat the will ofthe operator.

In the foregoing detailed.description'7 I" haveset forth theinvention `when utilizedin VtankV through said post'.L

a system wherein liquidis' pumpedfrom the tank l by a suction pump. In such systems, it is not uncommon for'waterto accumulate inthe bottom of.V theftank'jwhen the tankis adapted to contain gasoline.v ItYV is essentialV from time to time to remove'this water, but in accordance with 'the' present invention', this can bereadily 'done' by merely "removing the cap I'roni 'the topV of the hollow.' post,

attaching a pump at this ypoint/and pumping oit the water which vhas"accu'mu line, it is-the practice toadmit water under pressure (generally pr essure y off the city e it inthe drawings.V i. Ihedevlce 1nI practice lated. in lthe tems, thewater and gasoline stratify, the lat-` i ter. remainingin the upper portion of the tankk and the1 former'in 'theVY lower portion" thereof. There is a clear line ofdemarcation is .thereupon ready to properlyfunction.

betweenV the gasoline andv water i underv these conditionsand itis for the purpose of per,- mitting theloat to properly operate under these conditionslthatthe'weight 28 is shown as associated witlilthe float'rod.`

When used in a hydraulic system offthe :characterdescribed5V the weight is adjusted at su'chp'osition on the rod that the float Iwill befbuoyant in water,'but not buoyant in gaso-r beunderstood'that the.'y less gasoline in .the

tank7 the Vhigher'iwillf'bethe water level and.V

consequently l:when 'used' inf thisV connection; the? conduits 119i and 120 `should be reversed withjire'spectpto thefyU tube,V sothatthe c'on-` V-duit 1.19 wouldl besecured to the leg DiS-"of the` U"tube and thev conduit '120 ksecured'to thel ,leg-f3? *This changeihaving been n'iade,l the system,' as shown', will operateas Wellin a hydralicv feed systemas'm a pump 'feedsvs-v ternV and `will function Vin substantially the saine manner. It may-be desirable; however, when thusemploying the invention inya hydraulicsystem to positionitheffinger 34 on thev opposite sideof the cross vvvhead 38,1so that whenthe rod 35 is-elevated, it would forcey theffioat upwardly towardjgthe'top,o1c the tank and in a position oorresponding'to mini-v mum gasoline supply instead of 'forcing it downwardly as shown in thedrawings. This 'i195 slight. change,A however,will be apparent to those skilled, in the art and'ithas not been considered necessary to'speciiically illustrate is' extremely4 simple, but in: operation is very sensitive to the changes in position of theoat. "This is, in agi-eat measure, due to the factthjat the float has little if any'actual'vvork. to do. The only resistance,oii'eredfto-'the oat is the negligible friction ofthe bearings of the pivot. This is m pronounced' contradistinction to indicating` systems ofthe prior art wherein the ioatisv` required to move ai series 'of diaphragms, long columns of lliquid,'various `levers-,gears,and

dial pointers Theinventionhas been particularly described,r for? the `purpose of illusf tration; as used-'1n conjunctionwith gasoline supplyftanks, but it may-'loe employed to accurately indicate the' contentsof anyy tank. i

n lslight variation-of specific gravity ofthe liquid 1n the tank has absolutely no eifect on the acouracyof the readings intheisystem' Tof thisv invention,becausev this system meas fl lires-liquid levels. and not pressures. 1

` In practice, -theconduitsllQ and 12() preff l erably extend from the ground level to the casing of the U tube l through a common conduit, generally BX cable whereby both con# duitsare subjected to like variations in'y temperature and therefore expansion or contractionV of theair in said conduits has Vno edect upon the readings. It will -be noted, more- M over, that'the apparatus embodies, in its normal operation, only one movable-part having pivotal connection and consequently wear is negligible.

'The foregoing Vdetailedf description deals s with theinvention inits. preferred practical form, but the invention isV to be understood as fully commensurate with 'the` appended claims.' f

Having thus fully described the invention,

what I cla'im'as newanddsiretosecu by Letters Patent is; Y

Y l. 'In a" liquid level iindicjatingsysteim indicating 'element operable-bydiliferential .Y pressures, in combination with a. controlling element embodying @cylinder block having a cylinder therein and mounted to V'osci'llate on a substantially horizontal axis and shaped so that the opposite endsY ofthe *cylinder eX#lk tend upwardly above the intermediate porf tion ofthe cylinder,l a body4 of liquidewithin A the cylinder and forminga .liquidseal intermediate the ends ofthecylinder to divide thet interior of the cylinder into separate cham-V bers positioned above the surface ofthe liquid and sealed with respectsto one .another byrsaid body v0f liquid, the pivot-axis being Y so vlocated relative to the cylinder that, when the 'cylnderblock isy oscillated, the volumes of said chambers-are varied'inversely with respect to one another, vconduit leading from each of said chambers tothe indicatingelement for, communicating operating differ-V ential pressures thereto, aoat Vconnected to the cylinder block to oscillatethe same 'in laccordance with the risenand fall of -level Y of the body ofliquid to be measured, means for 'oscillating the cylinder block into a predetermined position, .and means for venting both conduits whilefthe cylinder block isin said predetermined position to free Vthe 1ndicatingelement of the differential pressures resulting from 'the .placing of; the cylinder bloc-k in said predetermined position.

2; In a liquid level indicating system, a

yU tube containing; a liquid `reading column,

and a reading scale associatedtherewith, in

combination with a controllingjelement emf l bodying a cylinder block having a cylinder tliereinand'mounted to oscillate on a substantially horizontal axis and shaped so thatthe opposite ends ofthe cylinder extend upwardlyabcve the intermediateportion of the cyle inder, ra body of liquid within the'cyhnderA` .and forming afliquidfseal'intermediate thel Vf ends ofthe cylinder to` divide'A the-interiori of the cylinder into separate chambers pocylinder to thefother Varm of the U tube, a

ioat connected to'thecylinder block to oscillate the same in accordance with the rise vand Vfall Vof'l'evel ofjthe body of liquid to be measured;- means for venting both conduits to permit the vliquid reading column in the f U. tube to assumea position whereinboth of its opposite ends are' at the same level,

irrespective Tof .the position ofY the cylinder block, and vmeans for moving the float to its" lowest operative positiom andmaintaining ittherewhile said conduits are vented.

e v3. In la liquid level' indicating system, a

U 'tube containing fa'fliquid reading column and af. reading scalefassociated therewith,

'said column tending to normally gravitate into a quiescent 'state with the opposite ends' of thev column atthe samezerole'vel, in com'- Y bination with a controlling element operable bythe level of the liquid to be measuredfor generating dierential pressures, "conduits leading fr'mthe'controllingelement to the arms of the U tube tocommunicate differential pressures to the opposite jendsofthe liquid reading'column therein, means for ventingsaid conduits tofpermit the liquid reading columnto assume zero positionirrespe-ctive ofthe level of tlieliquid to be measured, and means for placing the controlling element in a'condition corresponding toa predeter- V*mined* minimumlliquid level Vof the liquid to' be measured and for maintaining the controlduits are vented.` Y, e I L'An 'assembly'fof the'charact'er described c'omprisinga tank, a pipe leading to the ling element in this condition while the con?" tank',afliqui`d level indicating velement posi-V Y tioned exteriorly ofthe tankand operable Vby differential pressures, a supporting member extendingthrough the pipe into the tank,

afcylinder blockjhaving a cylinder therein` and pivotally mounted on the supporting `member!,toloscillateon a substantially horizontal axis and shaped' so thatcthe yOPlOo-` site ends of the cylinder eXtendupwardly der,-a liquid piston within the cylinder and forming,y ay liquid seall intermediate the ends of thefcylinder'. to divide' the interior "of the cylinder into two separate 'e chambers-positioned 4above the surface of Y vthe, liquid and sealedwith respec'ztl to one'k anotherY said body of'liquida float connectedfto thecylinder block to, oscillate said:

abovethe intermediate'por'tion of the cylinf eyiinaerftloekasthe iiquid'leyei in theme, .130

`mimos;

rises and falls, conduits connecting the chambers of the cylinder to the indicating element for communicating differential pressures Jfrom the cylinder to said element, said float and cylinder block being shaped and prof l portioned to be passed through the pipe leading to the tank When the parts are in predetermined relative positions, and means, operable from the exterior of thetank to place said parts in such relation. p

5. An assembly'of the character described comprising a tank, and a pipe leadingvinto the top of the tank in combinationl With a hollow support-ing post extending downwardly through said pipe and resting on the bottom of the tankand througl'i Which post liquid in the'tank may-be pumped out, a pressure i operated indicating element positioned eXteriorly of t-he tank, float` controlled pressure r producing means supported on the hollow post interiorly of the tank and shaped and proportionedv to be `introduced into and removed rom the tank through said pipe, and means extending through the pipeV for con- ;.i nesting the pressure producing means to the indicating element. Y j

6. In a liquid level indicating system, an underground tank,ja 1pipe `leading from the surface of the ground down to the tank and secured to the Wall thereof, a tubular post extending downwardly` through the pipe to substantially the bottom of the tank and through which post liquid can bev removed from the tank, and `liquid level indicating means, a portion of Whichis positioned within the tank and'is supported lon and carried by the tubular post.

In testimony whereofv I have signed lthe Y foregoing speciication.Vv Y

JACK D. SARTAKOFF. 

